A receptor-based biosensor for lipoprotein docking at the endothelial surface and vascular matrix

Area of Science:

• Biochemistry
• Materials Science
• Nanotechnology

Background:

• Proteoheparan sulfate (PHS) plays a role in lipoprotein interactions.
• Understanding lipoprotein deposition is crucial for atherosclerosis research.

Purpose of the Study:

• To investigate lipoprotein binding to PHS surfaces.
• To model early-stage arteriosclerotic nanoplaque formation.
• To evaluate the role of HDL and calcium in these processes.

Main Methods:

• Adsorption of PHS to methylated silica surfaces.
• Ellipsometric techniques to study binding kinetics.
• Analysis of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) interactions with PHS in the presence of calcium (Ca(2+)).

Main Results:

• PHS forms a monomolecular layer on silica, presenting glycosaminoglycan chains as binding sites.
• HDL exhibits high affinity for PHS and protects it from LDL and Ca(2+) complexation.
• LDL strongly deposits onto PHS, especially with Ca(2+), forming a ternary complex (proteoglycan-LDL-calcium), mimicking arteriosclerotic nanoplaques.
• HDL binding inhibits LDL deposition and subsequent calcification.
• HDL and garlic extract can reduce ternary complex formation and disintegrate aggregates.

Conclusions:

• The PHS-silica system effectively models lipoprotein deposition and early arteriosclerotic plaque formation at the nanoscale.
• HDL demonstrates a protective effect against LDL-induced plaque formation, consistent with clinical observations.
• This model system is valuable for studying lipoprotein interplay and for high-throughput screening of anti-atherosclerosis drugs.